Improvement in oscillating steam-engines



JOHN ROBERTSON.

Improvement in' Oscillating Steam-Engines.

Patented May 7,1872.

mummumlm IIH' " INIIIHW PATENT OFFICE.

JOHN ROBERTSON, OF BROOKLYN, NEW YORK.

IMPROVEMENT IN OSCILLATING STEAM-ENGINES.

Specification forming part of Letters Patent No. 126,576, dated May 7, 1872.

Specification describing an Improvement in Steam-Engines, the invention of JOHN ROB- ERTsoN, of Brooklyn, in the county of Kings and State of New York.

Thisinvention relates to that class of engines in which the piston or pistons are arranged to move in the arc of a circle. The invention consists in a combination, with a curved cylinder having a central abutment and valve-ports at the abutment, of a curved vibrating or rocking close piston of lesser area in its transverse section than the cylinder, and glands acting upon packings at the outer ends of the cylinder, for the piston to work through, substantially as hereinafter described, and whereby cheapness of construction is combined with efficiency of action.

In the accompanying drawing, which forms part of this specification, Figure 1 represents a sectional side elevation of a steam-engine constructed in accordance with my invention, and Fig. 2 a plan of the same.

Similar letters of reference indicate corresponding parts in both figures of the drawing.

A A is the cylinder of the engine, cast whole or in one piece, and of curved or segmental shape, so far as its interior or bore is concerned, with an abutment, B, in its center, dividing it into two segmental chambers, open at their outer ends. Said chambers may be of any desired shape in their transverse section, and do not require to be dressed or bored out, but simply clean cored, so that the cylinder requires no turning or boring for the piston moving within it. This is effected by the loose or free fit of the piston in the cylinder through stufting-boxes or glands G O acting on hemp or other packings b b at the outer ends of the chamber, in which the two ends of the piston move, and whereby leakage is prevented. By thus dispensing with the boring or dressing of the cylinder internally, great expense in the construction .of the engine is avoided over or as compared with those arrangements in which the piston has a close fit within its cylinder. D D is the piston, of a broken ring-like or curved construction, and close or solid at its ends or portions which work within the two chambers on either side of the abutment B. It is of symmetrical form throughout such portions to the full extent of its travel within said chambers and through the gland O C, and is of a shape in its transverse sections, at such portions, corresponding with that of the chambers or interior of the cylinder, but smaller, so as to be free from contact with the walls of chambers composing the cylinder. This piston D D is hung or suspended, as by an arm, 0, to rock upon or in a bearing, E, formed in common or one piece with the casting of which the cylinder is made. Its center of motion corresponds with the center from which the piston is struck, and from which the segmental shape of the interior of the cylinder is determined. G is a connecting-rod or jaw-shaped pitman attached to the rocking or oscillating piston D D, and serving to communicate rotary motion to a crank, H, of a main driving-shaft, I, which may be supported in bearings s .9, formed in one piece with the casting of which the cylinder is composed, or separately formed, as desired. On the shaft I is an eccentric, J, for operating the valve by which the engine is controlled. This valve may be an ordinary slide-valve, and serves to pass steam alternately into and out of or through ports d d on opposite sides of the abutment B, and to exhaust through a general outlet e for the purpose of driving the piston D D by alternately admitting steam to and exhausting from the reverse ends of the piston within the divided cylinder.

In this way, or by these means, a very simple, cheap, and efiicient engine may be pro duced; and, by the proximity to each other of the two chambers of which the cylinder is composed and the close arrangement of the ports 61 d to control both motions of the pistons, duplicate or compound engines, arranged side by side and using the steam from the one engine expansively in the other, may be very advantageously employed by reason of the shortness of the passages necessary to convey the steam from the one engine to the other.,

In some cases the connecting-rod G may be dispensed with, and the arm 0 of the piston solid pistonsD D,0f smaller area in their trans- D D be extended, and a radial slot made in it verse section than the cylinder, the glands or for the pin of the crank H to play in, and smiling-boxes G O, and the valve-ports d d 0, whereby the crank is operated in a direct manall arranged substantially as specified. ner from the piston. JOHN ROBERTSON.

\Vhat is here claimed, and desired to be secured by Letters Patent, is-

The combination, with the curved cylinder A A and its central abutment B, of the curved Witnesses:

FRED. HAYNES, R. E. RABEAU. 

